CO2402 Advanced Programming with C++ Lecture 6 Notes

CO2402: Advanced Programming
with C++ Lecture 6

Constructors in C++

1. Introduction to Constructors

o Constructors are special member functions in a class that are
automatically called when an object is instantiated. They
initialize the object's data members.

Example: The StackClass constructor initializes the stack top to 0.




2. Syntax and Characteristics

o A constructor has the same name as the class and no return type,
not even void.

o It can be defined with or without parameters. The version without
parameters is called the default constructor.

Example:

, 3. Function Overloading with Constructors

o Constructors can be overloaded to allow different ways of initializing
an object. Each constructor must have a unique parameter list.

Example:




4. Initialisation Section

o The initialization section can be used to initialize class members
before entering the constructor body. It appears after the
constructor's parameter list and starts with a colon.

Example:




5. Best Practices

o Always provide a constructor to ensure proper initialization of
objects.

o If no constructor is defined, C++ provides a default constructor.
However, relying on the compiler-generated constructor can be
risky, as it may not initialize data members properly.